Detection of Escape Peaks in Environmental Gamma Spectrometry
Keywords:
Gamma Spectrometry, NORM, Pair Production, Single Escape, Double Escape.Abstract
Pair production (PP) events are observed with gamma spectrometry when investigated samples emit sufficient numbers of photons with energies greater than 1.022 MeV. Because this condition is not typical of environmental samples, detection of PP is uncommon for environmental radioactivity. Nonetheless, this work experimentally demonstrated the detection of PP for an environmental sample of relatively high amount of the natural, radioactive isotope of potassium 40K, utilizing low background gamma spectrometry with sufficiently long counting times. Such detection was spectrally seen through the escape events of the annihilation photons that typically follow PP.
References
IAEA. Measurements of radionuclides in food and the environment. Vienna: IAEA; 1989.
Knoll GF. Radiation detection and measurement. Wiley; 2000.
Johnson JR, Mann KC. Single and double escape peaks in Ge(Li) gamma-ray spectra. Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 112:601-602 (1973).
Chao JH. Single-to-double escape peak ratio of germanium detectors. Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 317: 537-540 (1992).
Sardari D , Baghini NM. Escape probability of 511 keV annihilation photons from HPGe detectors. Radiation Measurements. 39: 387-390 (2004).